Under Robert's Rules of Order Newly Revised (RONR), if no time or method has been fixed to reconvene the assembly, the adjournment has the effect of dissolving the body.
[3] When a body has completed the scheduled order of business at a meeting and there is no further business for the assembly to consider at that time, the chair may simply declare the meeting adjourned without a motion having been made.
Like RONR, TSC considers it a privileged motion (and thus non-debatable) when business is pending.
[6] Unlike under RONR, however, it is considered a main motion (debatable and amendable) when no business is pending.
[12] In March 1835, there was controversy on whether Congress could stay in session past the end of the term without adjourning.
This issue was resolved when the Twentieth Amendment to the United States Constitution set a specific date and time for the start of a new session.